Debian Security Advisory

DLA-2780-1 ruby2.3 -- LTS security update

Date Reported:
13 Oct 2021
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 990815.
In Mitre's CVE dictionary: CVE-2021-31799, CVE-2021-31810, CVE-2021-32066.
More information:

Multiple vulnerabilites in ruby2.3, interpreter of object-oriented scripting language Ruby, were discovered.

  • CVE-2021-31799

    In RDoc 3.11 through 6.x before 6.3.1, as distributed with Ruby through 2.3.3, it is possible to execute arbitrary code via | and tags in a filename.

  • CVE-2021-31810

    An issue was discovered in Ruby through 2.3.3. A malicious FTP server can use the PASV response to trick Net::FTP into connecting back to a given IP address and port. This potentially makes curl extract information about services that are otherwise private and not disclosed (e.g., the attacker can conduct port scans and service banner extractions).

  • CVE-2021-32066

    An issue was discovered in Ruby through 2.3.3. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."

For Debian 9 stretch, these problems have been fixed in version 2.3.3-1+deb9u10.

We recommend that you upgrade your ruby2.3 packages.

For the detailed security status of ruby2.3 please refer to its security tracker page at:

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: